Cellular telephones communicate with a cellular network (e.g., cellular base stations) over wireless communication channels. The signal quality perceived by a user depends on several factors, including the strength of the received signal (e.g., the signal-to-noise ratio or bit error rate) and the presence of interference (e.g., due to multi-path effects). When the cellular telephone is located in an environment in which received signal strengths are very low, the cellular telephone and the network may be incapable of maintaining a communication session, and the session may unexpectedly terminate. In colloquial terms, this typically is referred to as a “dropped call.” An environment of low signal strengths also may preclude a cellular telephone from re-establishing a dropped call, or from establishing a new call with the network.
Most cellular telephone displays include a display element, referred to as a received signal strength indicator (RSSI), which reflects the strength of a received signal from the network. More particularly, during an ongoing communication session, the RSSI reflects measurements of the strength of a signal received over a communication channel that is allocated to the communication session. When a communication session is not in progress, the RSSI may reflect measurements of the strength of a control channel signal.
A typical RSSI includes a variable number of “bars” or other indicia. The number of bars displayed at any given time (and/or the relative heights of the bars) may be proportional to the measured, received signal strength. Accordingly, for example, when a received signal strength is very high, a maximum number of bars may be displayed, and when the received signal strength is very low, a minimum number of bars may be displayed. When the received signal strength falls below a low signal threshold, the cellular telephone may display zero bars, which indicates the presence of “no signal.”
During a communication session, observation of the RSSI may enable a user to determine whether the received signal strength may be degrading to a point where an undesired communication session failure is likely to occur. In addition, during the process of attempting to establish a communication session, a user may observe the RSSI to determine whether the received signal strength is likely to be adequate to establish a new connection with the network. When a user observes that the RSSI indicates a low received signal strength, the user may attempt to relocate the telephone to an area in which a higher received signal strength is present. However, a user may not realize that a typical wireless device makes received signal strength measurements fairly infrequently (e.g., only once every 10-15 seconds). In addition, the RSSI may not accurately reflect an actual received signal strength measurement. Instead, a typical RSSI reflects an average of multiple, previous received signal strength measurements. Not realizing these calculation characteristics of the RSSI, a user may rapidly move the cellular telephone around in an attempt to find the presence of a higher strength received signal.
Dropped calls, the inability to establish calls, and difficulty in finding areas of high signal strength are a common frustration among users. Similar signal strength-related issues also may plague other types of wireless networks (e.g., wireless local area networks, radio networks, and other wireless networks). Accordingly, network providers and wireless communication device manufacturers continuously strive to improve signal levels in coverage areas, expand coverage areas, and develop hardware and software that may better compensate for received signals having low signal strengths. Regardless of these improvements, areas will continue to exist in which received signals will be too low to maintain communications sessions or to enable new sessions to be established. Therefore, what are needed are apparatus and methods to enable a user to more readily locate areas in which received signal strengths are adequate for robust communications with a wireless network. Other desirable features and characteristics of the present inventive subject matter will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.